1. Field of the Invention
This invention relates to a winding fabrication method and apparatus for electric coils. More particularly, the invention relates to a winding fabrication method and apparatus for winding a conductive wire material by use of a rotary mechanism and forming an electric coil.
2. Description of the Related Art
A winding fabrication apparatus has been used in the past to fabricate a driving coil of a voice coil motor used for a linear motor for achieving linear driving and an induction heating coil for radio frequency induction heating into a winding state.
This winding fabrication apparatus includes a wire material feed portion 52 to which a bobbin 51 having a conductor wire material CW wound thereon is rotatably fitted, and a mold rotating portion 54 to which a coil-winding mold 53 for winding the conductor wire material CW is fitted and which drives and rotates the coil-winding mold 53, as shown in FIG. 5 of the accompanying drawings. Incidentally, the conductor wire material CW wound on the winding portion 530 of the coil-winding mold 53 is generally shaped to a straight angle so that winding can be easily conducted.
When the mold rotating portion 54 of the winding fabrication apparatus 50 rotates the coil-winding mold 53, the conductor wire material CW wound on the bobbin 51 fitted to the wire feed portion 52 is wound on the winding portion 530 of the coil-winding mold 53, and an electric coil in the winding form can be fabricated.
The driving coil of the voice coil motor and the induction-heating coil mostly have a rectangular shape or an elliptic shape. Therefore, the winding portion 530 of the coil-winding mold 53 fitted to the mold-rotating portion 54 is formed into a shape capable of forming the rectangular or elliptic shape. When the mold-rotating portion 54 rotates the coil-winding mold 53 having the rectangular or elliptic winding portion 530, an electric coil having a rectangular or elliptic shape can be acquired.
When the mold-rotating portion 54 rotates the coil-winding mold 53 having the winding portion 530 shaped into the rectangle or ellipse in the winding fabrication apparatus 50 described above, however, the conductor wire material CW supplied from the wire material feed portion 52 moves from a position A to a position Axe2x80x2 and then to a position Axe2x80x3 in FIG. 5. In other words, since the moving distance of the conductor wire material CW supplied from the wire material feed portion 52 from the position A gets elongated, large tension is imparted to the conductor wire material CW at a minor side portion 530a. At a major side portion 530b, on the other hand, small tension is imparted because the moving distance of the conductor wire material CW supplied from the wire material feed portion 52 from the position A is small. In consequence, the conductor wire material CW cannot be tightly wound in some cases at the major side portion 530b of the winding portion 530.
Consequently, the winding WI is tightly wound on the winding portion 530 at the minor side portion 530a as shown in FIG. 6A but is loose at the major side portion 530b, creating a gap with the winding portion 530. In this way, the conductor wire material CW undergoes floating and deformation and is not sometimes wound into an accurate size.
When the winding WI is rolled (press molded) towards the major side portion 530b of the winding portion 530 as shown in FIG. 6B, the gap occurring at this major side portion 530b can be prevented. However, because the winding WI is elongated at the minor side portion 530a, dimensional accuracy gets deteriorated.
To solve the problems with the prior art described above, the invention is directed to provide a winding fabrication method and apparatus for electric coils that can wind a conductor wire material into an accurate size without causing floating and deformation.
To accomplish the object described above, the invention provides a winding fabrication method for electric coils for winding a conductor wire material supplied from a wire material feed portion into an electric coil having a desired coil shape by turning a coil-winding mold having a winding portion that is formed into a shape having a linear portion having a predetermined length, the method comprising the step of linearly moving the coil-winding mold in a direction away from the wire material feed portion and imparting predetermined tension to the conductor wire material when the conductor wire material is wound on the linear portion of the coil-winding mold having the predetermined length.
According to the winding fabrication method for electric coils of the invention, the coil-winding mold is moved linearly in a direction away from the wire material feed portion to impart the predetermined tension to the conductor wire material when the conductor wire material is wound on the linear portion of the coil-winding mold having the predetermined length, whereby it becomes possible that the conductor wire material to be wound on the linear portion of the coil-winding mold is prevented from being floating from the coil-winding mold.
When the shape of the winding portion of the coil-winding mold is polygonal in the winding fabrication method for electric coils according to the invention, the coil-winding mold is linearly moved at a linear portion having a predetermined length in a direction away from a wire material feed portion by a distance corresponding to the length of the linear portion having the predetermined length, and is rotated at a corner. When the polygon as the shape of the winding portion of the coil-winding mold is a rectangle, the coil-winding mold is linearly moved at a major side portion as the linear portion having the predetermined length in the direction away from the wire material feed portion by a distance corresponding to the length of the linear portion having the predetermined length, and is rotated at a corner and a minor side portion. When the shape of the winding portion of the coil-winding mold is an ellipse, the coil-winding mold is linearly moved at the linear portion having the predetermined length away from the wire material feed portion by a distance corresponding to the length of the linear portion having the predetermined length, and is rotated at a semi-circle portion. Since it becomes possible in this way to prevent the winding position of the conductor wire material supplied from the wire material feed portion from deviating from the wire material feed portion, it becomes also possible to prevent the change of tension imparted to the conductor wire material depending on the position of the winding portion of the coil-winding mold.
When the conductor wire material is wound on the winding portion of the coil-winding mold in the winding fabrication method for electric coils according to the invention, the conductor wire material is preferably rolled towards the coil-winding mold. Since the conductor wire material can be thus wound under a stable condition on the coil-winding mold, the electric coil can be wound uniformly.
A winding fabrication apparatus for electric coils according to the invention for accomplishing the object described above is a winding fabrication apparatus for winding a conductor wire material supplied from a wire material feed portion into an electric coil having a desired coil shape by turning a coil-winding mold having a winding portion that is shaped into a shape having a linear portion having a predetermined length, wherein: when the winding portion to which the coil-winding mold is fixed and on which the conductor wire material is wound is the linear portion having the predetermined length, the apparatus includes a linear moving mechanism for linearly moving the coil-winding mold in a direction away from the wire material feed portion by a distance corresponding to the length of the linear portion having the predetermined length, and imparting predetermined tension to the conductive wire material, and a rotary base for fixing the linear moving mechanism; and when the winding portion on which the conductive wire material is wound is different from the linear portion having the predetermined length, such as a corner, the apparatus includes a rotary mechanism for rotating the rotary base to which the linear moving mechanism is fixed.
According to the winding fabrication apparatus for electric coils described above, when the conductor wire material is wound on the coil-winding mold, the linear moving mechanism linearly moves the coil-winding mold at the linear portion having the predetermined length of the winding portion of the coil-winding mold by a distance corresponding to the length of the linear portion, and when the winding portion is different from the linear portion having the predetermined length such as a corner, the rotating mechanism rotates the rotary base at an angle of rotation corresponding to the portion different from the linear portion. Since it becomes thus possible to prevent the winding position of the conductor wire material supplied from the wire material feed portion from deviating from the linear material feed portion, it becomes also possible to prevent the change of tension imparted to the conductor wire material depending on the position of the winding portion of the coil-winding mold.
When the conductor wire material is wound on the coil-winding mold in the winding fabrication apparatus for electric coils according to the invention, the apparatus preferably includes a pressure roller for rolling the conductor wire material towards the coil-winding mold. In this case, the electric coil can be uniformly wound because it can be wound under the stable condition on the winding portion of the coil-winding mold.